Centrifugal abrasive projecting machine



June 13, 1939. c. E. UNGER CENTRIF'UGAL ABRASIVE PROJECTING MACHINE 4 Sheets-Sheet l g ATTORNEY Filed Oct. 7, 1938 June 13, 1939. c. E, UNGER CENTRIFUGAL ABRASIVE PROJECTING MACHINE Filed Oct. 7, 1938 4 Sheets-Sheet 2 June 13, 1939. c. E. UNGER CENTBIFUGAL AsgAswE PROJE STING MACHINE 4 Sheets-Sheet 3 Filed Oct. '7, 1938 June 13, 1939- c. E. UNGER CENTRIFUGAL ABR ASIVE FROJECTING MACHINE 7 Filed Oct. '7, 1938 4 Sheets-Sheet 4 INVENTOR C'Igesler If. Fig/"er 620 i 4 ATTORNEY Patented June 13, 1939 UNITED STATES PATENT OFFICE 2,162,139 OENTBIFUGAL ABRASIVEPROJECTING MACHINE Application October 7, 1938, Serial No. 233,741

21 Claims.

This invention relates to an improved centrifugal abrasive projecting machine designed to throw abrasive in a directed stream at. velocities effective to clean the surfaces of castings, forgings, bars, sheets and like metallic objects so as to remove encrusted sand and scale from the surface thereof.

Centrifugal abrasive projecting machines now in use comprise a rotor head mounted for rotation at high speeds having a plurality of abrasive projecting blades mounted thereon which extend inwardly short of the axis of rotation of the rotor head to provide a central abrasive receiving space. A normally stationary tubular control memberextends into the said central space and is provided with a discharge outlet in the tubular sidewall thereof. An impeller :comprising a plurality of spaced abrasive propelling vanes is positioned within said control member and is fixed to rotate with said rotor head. Abrasive supplied to said propeller by a feed pipe is thrown by the impeller vanes outwardly through the discharge outlet in the tubular control member, where it is picked up by the inner ends of the rotating blades and thrown against the work piece to be cleaned or treated.

It will be appreciated that in a structure of the type above described, operating clearances must be provided between the rapidly rotating impeller vanes and the normally stationary tubular control member within which the propeller vanes are positioned. Abrasives normally used for blast cleaning and treating of metal objects comprise shot, which materials are free-flowing. Such clearance space provided between the impeller vanes and the tubular control member, which uncontrolled 7 abrasive is commonly designated as stray abrasive. This stray abrasive continues its irregular movement through this clearance space,

rebounding between the rotating neck portion of the impeller at the rear of the impeller vanes and the stationary tubular control member, where it exerts a grinding wear upon the adjacent stationary and moving parts 01' the machine.

It has heretofore been attempted to reduce the quantity of stray abrasive moving rearwardly of the rotor by the provision of a circular rim or flange extending inwardly from the inner end of the tubular control member, which flange seats behind the impeller vanes. It' will be appreciated 10 ,that, operating clearances must also be provided between the inner edge of t flange and the neck portion of the rotating impeller. It is therefore impossible to completely seal this clearance space between the rotating impeller and the stationary 15 tubular control member with any mechanical element so as to prevent the rearward movement of this stray abrasive.

The stray abrasive lodging between the normallystationarytubular control member and the 2 0 rotating parts of the propeller eventually escapes by passing around the inturned flange of the tubular .control member, where centrifugal force acts upon the freed stray abrasive to cause it to fly outward. This outward flying abrasive, free 25 of the tubular control member, is picked up by the abrasive propelling blades and is thrown ,helter-skelter in all directions. This uncontrolled stray abrasive has a severe abrading action, due to the velocity imparted to it by the rotating blades, with the result that it wears the protective casings and other mechanisms surrounding the rotor, without coming into cleaning contact with the work piece positioned at one side of the rotor. It will also be appreciated that this stray abrasive is'broken up and damaged without doing any useful work, but actually doing destructive work. This stray abrasive, free of, the tubular control member, is often thrown against the rotor'head during its outward move- 40 ment, with the result that the adjacent rotor head and other parts of the machine are also abraded thereby. f

It will also be appreciated that the flange portion extending inwardly from the inner end of the 4 tubular control member must also be accurately centered with respect to theneck portion of the rotating propeller and must also be properly spaced between the adjacent impeller vanes and the rear wall surface of the rotor head to provide proper operating clearances between these points. When the impeller is in position, it is difllcult, if not impossible, to visually determine whether proper axial and lateral clearances are provided between the normally stationary inturned flange of such a tubular control member and the rotating parts of the mechanism. When the tubular control member is improperly positioned, there is further severe grinding between the stationary and moving parts. It will ,also be appreciated that such tubular control member cannot be removed from the machine without flrstremoving the impeller so that considerable time is required in adjusting, removing and replacing worn operating parts.

It is an object of this invention to improve upon centrifugal projecting abrasive machines now in use so as firing qualities and operating efficiencies and to relieve operating parts of the machine from damaging wear caused by stray abrasive.

Another object of this invention is to provide an improved centrifugal abrasive projecting machine having means to relieve the machine of such stray abrasive and abrasive lines which cannot be controlled in such a manner that this material will be discharged substantially without 7 abrading or wearing velocity.

' Another object of this invention is to provide an improved abrasive control device which is. provided with means for-conducting rearwardly moving stray abrasive and abrasive fines back to a position where it may be discharged from the abrasive discharge outlet provided in said abrasive control device.

Another object of this invention is to provide an improved abrasive impeller designed to be sitioned within the tubular control member a bladed abrasive throwing rotor which impel r is provided with means to create an air current moving in such a direction as to substantially prevent any rearward movement of stray abrasive and abrasive-fines through the clearance between the rotating propeller and the normally stationary tubular control member.

Another object of this vention is to provide an improved directional control device and impeller device having co-operating means which greatly limit or prevent rearward movement of stray abrasive and which perform the further function of returning such stray abrasive to a point where it can be engaged by the rotating impeller and thrown through the abrasive outlet provided in the control device.

A further object of this invention is to provide an improved centrifugal abrasive projecting machine having means for balancing air pressures within said hine during rotation thereof and remove objec onable movements of the abrasive insaid machine caused by undesirable air currentsand air disturbances.

'Variousother features and advantages of the invention will be apparent from the following description and from an inspection of the accompanying drawings.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, and the manner in which it may be car-' ried out, may be better understoodby referring to the following description taken inv connection with the accompanying, drawings forming a part thereof, in which:

Fig. 1 is a side elevational view of'the improved brackets for adjustably mounting the feed spout and tubular control member;

Fig.2 is a vertical cross-sectional view of the abrasive throwing wheel, showing certain details to obtain improved particularly the of the improved tubular control member and impeller with abrasive and air vent passages in the hub of the wheel, this'view also showing in section the supporting brackets upon which the feed shout and tubular control member are adjustably supported, this view being taken on line .2--2 of and impeller, a fragmentary portion of the tubular control member being broken away to more clearly show the vent passages in the hub, this view being taken along lines 5-! of Fig. 2;

Fig. 6 is a perspective view of the abrasive impeller, the impeller being positioned centrally of the rotor when assembled thereto;

Fig. 7. is a side elevational view of the tubular control member, certain parts thereof being.

broken away to more clearly illustrate the interior construction thereof; a

Fig.8 is a transverse cross-sectionalview of the hub as it appears when removed from the wheel, and when looking ata section 'thereof in the direction of the arrows 8-8 on Fig. 2;

Fig. 9 is a top plan view of the feed funnel, feed pipe and supporting bracket as it appears when looking inthe direction of the arrows 9-8 on Hg. 1;

associated tubular control Fig. 10 is a crow-sectional view taken at the A juncture of the feed funnel and the feed spout looking in the direction of the arrows Ill-ll on 'Fig. 11 is a cross-sectional view of the feed spout and supporting bracket therefor, this view being taken on line ll-ll of Fig. 1;

Fig. 12 .is a cross-sectional view through a portion of the tubular control member and its supporting bracket, this view'being taken along line I lI-II of Fig. l; and

Fig. i3 is a side elevational view of the feed spout and control cage supporting bracket;

Similar reference characters refer to similar parts throughout the drawings and specification.

Referring more particularly to Figs. -1 to 4 inclusive of the drawings, the improved centrifugal abrasive projecting machine comprises a rotor structure W supported by a hub it carried by a shaft 2i adapted to be rotated at high speed.

The rotor W comprises more particularly a side wall plate I of generally circular form upon which is rotatively supported a plurality of generally radially extending abrasive propelling blades 2: which extend inwardly short of the axis of rotation to define a central space 8 which receives a tubular control member 0. An impeller member i, which may be formed as a one piece casting, is positioned within the tubular control member 0 and is fixed to the hub h so as to rotate therewith. An abrasive supply conduit 1 is provided which is arranged in inclined position to feed the abrasive into the impeller member i.

The blades 1) maybe conveniently mounted upon the rotor plate I by providing a second rotor' I I 2,162,189 having reduced ends 4 which extend into openings bored in the rotor plates I and 2. It will be noted that the studs 3 are provided with shoulders 5 against which the plates I and 2 seat so as to hold them in flxed spaced relation, the studs 3 being permanently connected with the plates I and 2 by welding 6 at the reduced ends l of the'studs 3. I

It will be noted, by referring to Fig; 2,'that both the rotor plates I and 2 areeach provided with a central opening 1, whose peripheral edges are generally in axial alignment with the interior ends I2 of the blades b, thus providing a truly circular central space 3 within which the tubular control member is received. By referring more particularly to Figs. 2 and 3 it will be noted that the rotor plates I and 2 are also provided with a plurality of radially extending grooves 3 whichare arranged in pairs so as to receivethe respective adjacent side edges of the blades b. i

The blades b arepreferably made of a metallic material which is resistant to abrasive wear and is sufllciently tough and strong to stand up under the shocks incident to operation. Each ofthe blades b comprise generally a bottom wall portion 60 which may be of increased thickness at the outer end I3 thereof and which tapers to an edge at the inner end I2 thereof as shown in Fig. 3. Side flanges I I extend along each side edge of the blade which are preferably of uniform height throughout so as to rather snugly fit within the grooves 3 provided in the rotor plates I and 2. Each blade b may be held in fixed operative position by a threaded set screw I5 which extends through a threaded aperture in the rotor plate 2 and which is provided with a tapered inner end I6 which seats within a half conical groove ll provided on the rear face of the blade b. The outside face of each set screw I5 when in operative position is substantially flush with the outside face of the rotor plate 2, and may be provided with a tool engaging slot I I intowhich a screw driver or other tool may be inserted to manipulate the set screw. It will be? appreciated that the blades 1) may be quickly'and easily removed by partially withdrawing the st screw I5 so as to permit the blades b to slip out through the periphery of the rotor. The blades however are fixedly held in secure operative position when the set screw I5 is turned inward so that the conical end Ii seats within the half conical recesses I4 in the blade. All of the blades b of the rotor may be similar in construction. and similarly mounted.

The hub h may be made from a single casting comprising a sleeve portion 20 and a heavy flange portion 23a which has a large central bore into whichithe end of the drive-shaftjl snugly fits. The drive shaft 2I may-be fixedly 'held to the hub 72 by one or more splines 22. As thus assembled, it' will be noted that the interior end of the shaft 2I is visible through-the central space of the rotor prior to the insertion of the impeller i. The hub h is secured to the rotor by means of aplurality of spaced threaded bolts 23 which extend through the hub flange a and into threaded apertures in the rotor plate I. Aring covering 24 of rubber or other abrasiveresisting material maybe attached to the peripheral edge of the flange portion 20a of the hub so as to protect theflange portion from the abradlng action of rebounding abrasives.

The control member 0 is tubular in cross-section and has a substantially truly cylindrical ex- -to Fig. 2 that when .3 terior surface. The control member is provided with an abrasive discharge outlet 32 of generally limited peripherab length. Assuming that the rotor shown in Fig. 3 is rotating clock-wise, the abrasive would be thrown out of the discharge opening 32 of the control member by the impeller i in a stream flowing somewhat to the right of the radial line. To facilitate ejection of the abrasive, a forward edge 34 of the discharge outlet 32 may be inclined as shown in Fig. 3, while the rear edge 33 of the outlet 32 may or may not be so inclined. If desired, the walls of the tubular control member may be slightly thickened at the point 34 which part normally receives the greatest wear. It will also be noted by referring to Fig. 2 that the side edges II of the discharge outlet 32 reside slightly within and between the inside faces of the flanges II of the blades. If desired, the inside faces of the flanges II of the blades adjacent their inner ends may be tapered inwardly as at I 8 to assist in guiding the abrasive from the discharge outlet wall portion III of the blade.

It' will be noted by referring more particularly the tubular control member 0 is in operative position, the interior end 38 there- 32 on to the bottom of extends into a circular-recess 23 provided inthe hub 72, such clearance being provided to permit free rotation of the hub h while the tubular control member 0 remains stationary. leading outwardly from the circular recesses 29 in the flange portion 20a of the hub h, is a plurality of vent passages 25. As will be more fully brought vent passage 8, so as to further facilitate abrasive through the vent a heavy angle iron her 0 may; be cut away out hereafter, the circular recess 29 in which the interior end 36 of the tubular control member 0 extends is adapted to receive any stray abrasive that may work its way rearwardly of the rotor, this abrasive then being promptly ejected through the vent passages 25. It will be noted that the vent passages are relatively close to the shaft 2| and the axis of rotation of the rotor so that any stray abrasive that may be ejected from the has no substantial abrading velocity and consequently does little or no damage I I to the surrounding mechanism.

While I have shown a vent passage 25 for each blade of the wheel, it number of vent passages may be provided. Each vent passage 25 is defined by a lower wall 26 and a top wall 21 and substantially parallel side walls 28. The top wall 21 and the bottom wall 26 flare apart outwardly so that the opening of the passage at the end where it leads into the circular recesses 25 is larger at the discharge end than 29. The circular recesses 23 may bemut out or depressed at points 3| adjacent each vent passage 25, as shown particularly in Figures 5 and passages.

The upper portion of the tubular-control memat the point where it emerges beyond the rotor disk 2 so as to provide entrance room for the discharge end-of the feed pipej. -The lower half portionof the tubular control member 0 may be provided with an outwardly extending arcuate foot or saddle portion 31 which provides means for rigidly securing the tubular control member to a suitable support.

The tubular control feed funnel 12 may be rigidly but adjustedly sup, ported upon a suitable support which will now be described. A fixed and rigidly mounted'platform positioned in front ofthe rotor, supports ,the bracket structure. This the outflow of stray platform may comprise having a generally horizon will be appreciated that any member 0 feed about I and. k

4 tall extending support flange II and ,a downwardly extending stiffening flange III. A flat plate 81a may also be positioned upon the horizontal flange seat for a main supporting bracket 82, which bracket comprises an upwardly extending flange portion 58 and a horizontal extending foot portion 54 which sets upon the plate 51, a stiffening web 58 joining the flange portion 58 to the foot portion 84. As shown more particularly in Figs. 1, 12 and 13, a pair of bolts 58 are provided which extend through elongated slotslia in the foot portion 54 of the bracket and through circular openings in the plate 51a and,flange 5|. Thus the foot portion it of ,the bracket may be moved a certain amount to theright or left as shown in Fig. 1 for a purpose which will hereafter be brought out. The tubular control member is supported upon an arcuate shaped saddle "which is connected to flange 88 of the main bracket 82 by a secondary bracket 51., The secondary bracket 51 is provided with a vertically extending leg portion '58 which seats against the flat face of the flange 88 on the main bracket," bracket 51 being held thereto by a pair of spaced bolts 88 as shownin Fig. 11' which 'extehd throilgh horizontally elongated slots m provided in, 'the leg portion 88 and through verticallyelongated -apertures 88a in the flange por- 7 tion 58 of the main bracket. The secondary bracket, is provided with a horizontally extending leg portion ll whic is also provided with horf izontally elongated slots 82a through which bolts 82 extend, the bolts 82 extending through circa- .a circular aperture 18 in lar apertures in the handle portion 88 of the saddle 88.

. Referring more particularly to Figs. 1, 2 and 12, it will be noted that the saddle 88 is provided with a generally arcuate surface 88 which extends under the saddle portion 81 of the tubular control member c'and generally conforms to the circular contour thereof. aruate foot portion 88 which rests upon the saddle 88 and an arcuate belly portion 88a which extends into the saddle portion 81 of the tubular control member c and conforms generally to the contour thereof. A clamp bolt 61 extends through the clamping bar 65 and the head 88 of the bolt is of such size as to be insertable through an enlarged opening 89 in the saddle 88. When the clamping bar 65 with associated bolt 61 is pushed forwardly toward the rotor disc I the bolt head 88 slides into a bayonetslot 89a and in this position the nut on bolt 81 can be tightened to flrmly clamp the'clamping bar 88 in fixed position. Removal of the clamping bar can be effected by loosening the nut and the clamping bolt 81 sufliciently to permit outward withdrawal of the clamping bar" to the point-where the head of the bolt 88 will slip through the enlarged opening 88 in the saddle '88.

Abrasive is supplied to the impeller i and the tubular control member c through a feed spout 1' upon which is mounted a feed funnel 12 as shown more particularly .in Figs. 1, 2 and 9. The feed funnel 12 has an opening 81 in the bottom thereof in alignment with the open end of the feed spout f. The feed funnel 12 is provided with a secondary supporting bracket 18 which may be cast integrally therewitha The bracket 18 comprises a generally horizontal extending leg portion 18 and a vertically extending leg portion 15. The leg elongated slots 18:;- provided in the vertical leg II to provide a smooth and level A clamping bar 85 has an conduit portion 1|; the upper end of which is pro- 5 vided with laterally extending wing portions 11 as', shown' more particularly in Fig. 10. Each of the wing portions 11 are provided with a bayonet slot 11a through which a securing bolt 18 extends, the securing bolt 18 being threaded into a corresponding threaded aperture in the horizontal leg portion 14 of the. bracket 18. Thus, it will be noted that the feed conduit 1 is rigidly suspended from the horizontal leg portion 14 of the bracket 18 and can readily be removed by unloosening bolts 18. The funnel member 12 may be providedwlth a reenforcing web 18 which connects the funnel member 12 to the horizontal leg 14 of the bracket 18.

The discharge end of the conduit I may be provided with an outwardly flared flange 82 whose outside diameter approximates the inside diameter of the tubular wall 88 of the control member 0. The control member c may be provided with an inwardly extending circular rib 88 which overlaps the outwardly extending flange 82 of the feed conduit 1. The flange 82 may be so positioned that it substantially ,abuts the circular rib I8 when the feed conduit is in proper position for most eflicient feeding of the abrasive into the impeller i.

The impeller i may be made as a single casting preferably of some wear-resistant metal and is cast in the form shown in Fig. 6. The impeller generally comprises a circular rim or front wall portion 85 defining a central opening 88 and a circular rear wall portion 88 between which are supported a plurality of spaced radially extending impeller vanes 81. As shown in Fig. 6 the impeller vanes81 may be' cast integrally with the front wall portion 85 and the rear wall portion 88.

The rear wall portion 86 of the impeller is pro- '50 vided with a collar portion 88aextending rearwardly thereof which collar portion terminates in outwardly extendi'ngflange portion 88 which seats against the inside face of the hub member h. The

collar portion 88a has an axial length sufllcient to 5 properly space the impeller vanes 81 so that the impeller vanes will properly discharge the abrasive in a radial direction through the discharge outlet'82.

The impeller i is end of the drive shaft 2| by means of a threaded bolt fl'which hasa head 92a seated within a depressed recess 88 formedcentrally of the rear wall portion 88 of the impeller i. By referring to Fig.2 it will be noted that when the threaded bolt 04 82 is in proper position the top face of the head 92a of the bolt is substantially flush with l the inside face of the rear, wall portion 88.

Preferably it is desirable that impeller vanes 81 equal in number to the abrasive-throwing blades 7' b be provided, as illustrated more particularly in Fig. 3. The advancing faceof the impeller vanes 81 should bemositioned slightly in advance of the advancing face It of the propelling blades b so that the abrasive thrown by the impeller vanes v1 fixedly secured to the inner 6i through the discharge outlet 32 in the control member will be deposited gently onto the inner end of the corresponding abrasive propelling blade. In order that the impeller i will be properly mounted so as to place the advancing face of the propelling vanes 81 in proper advanced posi tion, the projecting end of the shaft spline 22 is arranged to extend into acorresponding slot provided in the inside face of the of the impeller i, as illustrated in Figs. 2 and 6. The impeller z is assembled to the rotor by inserting the same into the tubular control member 0 and inserting the inner end of the shaft spline 22 into the corresponding slot provided in the collar portion 88a of the impeller z. The securing bolt 92 is then inserted into a threaded aperture in the end of the drive shaft 2| and tightened so as to hold the impeller flanges 89 in face-clamping engagement with the inside face of the hub member h. It will be appreciated that the impeller can be quickly removed by first removing the feed spout j by loosening clamping bolt 18 and then removing the impeller bolt 92.

An important feature of this invention is the provisionof means for improving the directional control qualities of the bladed rotor and reducing the wear on the impeller i, the tubular control member .0 and the rotor w. Centrifugal abrasive-throwing mechanisms heretofore constructed comprising a bladed rotor, tubular control member and impeller permit, a certain amount of the abrasive to work its way rearwardly of the discharge outlet and between the tubular control member and the impeller. This abrasive is then ground between the stationary and moving parts of the machine destroying both the abrasive and seriously wearing these operative parts and in all directions.

In the improved construction disclosed in this application this difliculty is largely eliminated and improved directional firing and lessened wear of the operating parts isafiected by providing the interior-surface of the tubular portion 30 of the control member with an internal helical rib 4| which may be cast integrally with the tubular control member, as shown more particularly in Fig. 7. This helical rib 4| extends from the free edge 36 of the tubulancontrol member inwardly thereof ,to a plane intersecting the tubular control member at the rear side edge 35 of the discharge opening 32 and which plane is generally parallel to the rotor wall I. It will be seen by referring more particularly to Fig. 7 that the rib 4| spirals approximately 3 turns beginning at point 42 at the rear edge 36 of tubular control member and ending at point 43 generally in the plane above-mentioned. Thus a helical passage 44 is provided around the inside face of the tubular portion 30 of the control member 0 which passage is defined by adjacent rib portions 4|.

Referring again to the impeller i as shown;

more particularly in Fig. 6, it will be noted that the impeller is.provided with a pair ofdiametrically spaced web portions 93 extending between the rear wall portion 86 of the impeller and the rear flange portion 89 thereof. 'Assuming that the impeller is rotating in the direction of-the arrow shown in Fig. 6, the advancing face 94 of the web portions 93 function as a fan. Any stray abrasive not immediately discharged through the discharge opening 32 of the control member and Which works its way rearwardly between the inside face of the tubular control member and the collar portion 8811 when finally discharged is thrown the tubular control particles escaping through rear wall portion 86 of the impeller as through thespace marked a: the passage 44 between adjacent rib portions 4| of the tubular control member. As the impeller i rotates the web portions 93 will create an air current which will drivethe abrasive through the passage 44 in the direction of the arrow as shown in Fig. 7 and back out through the space a: between the rear wall portion 86 of the impeller and the inside face of the tubular control member where it can be again picked up by the impeller vanes 81 and hurled out through the discharge outlet 32 of the tubular control member. The rotating web portions 93 also create an air stream which the feed spout f and this moving current of air to a substantial extent prevents the entry of abrasive into the space .r.

Thus the helical passage 44 and the web portions 93 both cooperate to insure that practically all of the abrasive fed into the impeller i is thrown out through discharge outlet 32 of the control member will be deposited on the inner ends of the advancing blades at a predetermined point during rotation thereof.

When the abrasive ejected through the discharge outlet 32 is deposited upon the inner end of the blades at a predetermined point only, the abrasive will be thrown in a predetermined direction, depending upon the clock dial position in which the discharge opening 32 is placed.

It has been found by actual .test that the directional control characteristic of the improved -centrifugal abrasive impelling machine disclosed in this application is substantially greater than the best directional control results obtained by the best centrifugal abrasive? projecting machines heretofore constructed. This is due to the fact that susbtantially the impeller i is forced outwardly through the discharge opening 32 of the tubularcontrol member. Abrasive fines and other abrasive which normally tends to creep rearwardly of the rotor between the impeller and the tubular control member is largely prevented from such movement by the air stream created by the fan action of the web portions 93. If any such abrasive fines'or other abrasive does move rearwardly through the space a: between the impeller i and member c, it is guided back into the path of rotation of the impeller vanes 81 by the helical passage 44 through which it is driven by the fan action of the web portions 93.

Should any abrasive fines move rearwardly a sufiicient distance so as to be unaffected by the air current created by the revolving web portions 93, it will then pass into the circular recess 29 provided in the hub member h and readily escape through the vent passages 25 at such low velocity as to have no abrading or damaging effect on surrounding mechanisms. The stray abrasive the vent passages 25 flows axially outwards towards will find itself lodged within all of the abrasive fed into has been found to be substantially confined to V dust particles which are not susceptible of being eflectively thrown by the abrasive projecting blades b. It is believed that the air current created by the rotating web portions'93 causes the abrasive fines to stay within the groove 44 until discharged at the rear point 42 or front point 43 since numerous test runs clearly show that these stray abrasive fines exert no grinding or, damaging effectupon either the impeller i or the tubular control-member c, consequently these parts will last indefinitely as far as any grinding action of stray abrasive is concerned. The tubular con- .fines escaping from end l2 of the trol member first wears out at points adjacent the discharge outlet 32 due to the abrading effect of the discharging abrasive contacting the surrounding edges of the opening 32. Stray abrasive the helical passage at point 42 are immediately discharged into the circular recess ,23 in the hub from which point it is promptly ejected by ble'eder passages 25. No stray abrasive can work its way .around the inner end 36 of the control member and into space marked 11 since all the stray abrasive which reaches the circular recess 23 escapes thru the vent passages 25. v

The tubular control member may be accurately positioned within the central space 3 of the rotor w by the supporting brackets. It will be appreciated that it is important that the inner the outer surface of the tubular portion 30 of the control member 0 so as to provide proper operating clearances, and it is further important that the inner end 36 of the control member be inserted the desired distance into the circular recess 23 in the hub member h.

It will be noted that the tubular control member 0 may be shifted the desired amount to the right or'left as shown in Fig. 1 by loosening the bolts 62 and shifting the handle portion 63 of the saddle- 33 to the right or left which is permitted by the horizontally elongated slots 62a. in the horizontally extending leg portion 6|. The tubular control member 0 may be shifted axially of the rotor so as to properly position the interior end 36 thereof in the circular recess 23 in the hub simply by loosening the bolts 53 and shifting the secondary saddle supporting bracket 51' to the right or left as shown in Fig. 2. The tubular control member 0 may be vertically raised or lowered by loosening the bolts 53 and shifting the bracket 51 in a vertical directionwhich is permitted by the vertically elongated slots 53a in the flange portion 53 of the main bracket.

Likewise the feed spout f and associated funnel member 12 may be shifted in six different directions. The flange portion 32 of the feed spout f may be shifted axially of the wheel toward or away from the circular rib 33 of the associated tubular control member by loosening the bolts 16 asshown in Figs. 1, 2 and and shifting the downwardly extending leg portion 15 of the secondary bracket 13 to the right or the left as shown in Fig. 2. The discharge end of the feed spout I may be vertically raised or lowered by unloosening the bolts 16 and shifting vertical leg portion 15 of the secondary bracket 13 vertically which is permitted by the vertically elongated slots 53b provided in the flange portion 53 of the main bracket 52, which feature is more particularly shown in Fig. 13. g

The discharge end of the feed spout I may be shifted laterally to the right or left as shown in Fig. 1 by unloosening the bolts 13 and then shifting the feed spout f laterally to the right or left as shown in Fig. 1 which is permitted by the elongated slots 11b provided in wing portions 11 extending laterally from the upper 'end of the feed spout 1.

Thus it will be appreciated that the tubular control member 0 as well as the feed spout I and its associated funnel member 12 are both susceptible of a six-way adjustment so that these parts can be accurately centered most emcient operation. The adjustment is affected by merely loosening paired clamp bolts, shifting the parts in the desired direction and the blades 1) be'uniformly spaced from r ends of the blades side wall plates I and 2 i wear in the mechanism and positioned for desired amount and then tightening the clamp bolts so as to accurately hold these parts in the desired fixed position to which they have been adjusted. Thus the tubular control member 0 may be adjusted upward or left and axially in both directions so that the proper accurate clearance is provided between the interior ends l2 of the blades 17 and the outer surface of the tubular control member and further to position the interior control member in proper position within the circular abrasive-receiving recess 23 in the hub member h. Likewise the discharge end of the feed spout f may be vertically adjusted, laterally or downward, to the right 5 end 36 of the tubular 1 adjusted to the right or left, and axially adjusted 15 in both directions so as to properly center the outwardly extending flange portion 32 on the inner discharge end of the feed spout in proper position within the tubular control member 0 and in proper abutting relation to the circular rim 33 off to one side from the axis of rotation of the 25 rotor so as to give clear, unobstructed view of the control cage. The proper clearance between the outer surface of the control cage and inner b and the inner edges 1 of the be visibly determined and provided for. Clear unobstructed view is also provided for centering the flange 32 of the feed pipe in proper position within the tubular control member 0 and in proper abutting relation end 36 of the tubular control member may be inserted into the circular recess 23 in the hub' h the proper axial distance by providing a mark on the outer surface of the tubular control memof the wheel can thus to the rib 33. The inner 3 her so positioned as to align with the outside face of the side wall plate 2 when proper axial insertion of the tubular control member 0 has been effected. Proper and accurate positioning of the tubular control memberc and the feed pipe I with reference to the rotor 10 is thus assured.

Extensive "tests of the centrifugal abrasive machine disclosed in this application have shown that a higher degree of directional control of the thrown abrasive is attained than has ever been attainable by the best centrifugal abrasive projecting machine heretofore produced. This results from the fact that substantially no stray abrasive can pass on to the abrasive propelling blades b. Stray abrasive and abrasive flnes which may conceivably work its way rearwardly between the control member 0 and the impeller 1'. to the space a: is driven forwardly into the path of the impeller vanes 31 which throws this stray abrasive out through the discharge outlet 32 in'the control member 0 under directional control. Exten- 5O sive tests have further revealed that this tubular control cage is subjected to substantially no wear except only the wear around the inside surface of the tubular control member between the rib 33 and' the inner end which area is swept by abrasive, and the wear along the side edges 33. 34 and 35 of the discharge outlet 32 incident to the discharge of abrasive outwardly through the discharge outlet 32, and

tion has been found by actual test to be less than the wear in tubular control members heretofore constructed. Wear on the impeller 12 is also substantially confined to the advancing faces of the abrasive projecting vanes 36 thereof. The web 7 43 of the helical rib ,3;

described in this applica- 74 portions 93 serve to create a current of air which keeps stray abrasive away from the collar portion 88a and the flange portion 89 of the impeller,

so that these parts are subjected to substantially no wear.

It has been further found, from tests made of the machine herein disclosed that the blades b Any stray abrasive which reach the cireular recess v29 in thehub h is promptly discharged to the vent passages 25, and no abrasive works its way around the inner end 36 of the tubular control member and into the clearance space 1/ between the outside surface of the tubular control member and the inner peripheral edge I of current movements the side wall plate I. Thus the side wall plate I of the rotor is subjected to little or no wear during operation.

It will be appreciated that when a bladed abrasive throwing wheel is rotated at blasting velocity, air disturbances necessarily result, causing air within the central opening of the wheel, which, by rotation of the blades, is aregion of low pressure. Air flows into this central region through the feed spout or space surronding the feed spout and the tubular control member which is all positi ned on one side of the wheel, the re .side of the wheel in prior centrifugal wheels ing closed at the back. By the provision of ven or 'bleeder passages 25 through which air can ci culate freely either to enter the wheel or flow mm the wheel to stabilize and balance the pressure within the central region of the wheel, greatly improved results in directional control eillciency and reduced wear are obtained, since the disturbing air currents set up by the rotation of the bladed wheel are thus substantially obviated or the effect thereof greatly lessened.

With my improved chine as herein disclosed, actual tests have shown that little or no stray abrasive or abrasive lines are discharged from the vent openings, which is a further indication of the high directional control'. efliciency obtained. This highly desirable result appears to the impeller webs 93 in cooperation with the helical passages 44 in the tubular control member prevent the rearward movement of stray abrasive or return such stray abrasive to the interior of the tubular cows; member, and to the fact that air is swept into e central region-through the vents provided in the hub, which movement of air would :act to prevent the rearward movement of the stray abrasive so that the abrasive is retained in such position within the tubular control member that it can readily -be' propelled out through the the theory of its operation andthe movement of abrasive and air currents can only be conjectured,

since it is almost impossible to measure same under high speed operatingconditions.

It has been'founcl further, and demonstrated to be a fact, that in my improvedabrasive throwing machine, the exterior of the tubular control member evidences little sign of wear in operation, and that in my improved device thetubular control member is subjected to less abrasive wear than the tubular control members in prior art reason of the high speedcentrifugal blasting ma-- be attributable to the fact that discharge outlet therein by the impeller. While the highly desirable results pro-- devices. Any back-sweep oi abrasive-laden air around the exterior of the tubular control member appears to be eliminated, as evidenced by the fact that there is little sign of wear on the exterior surface of the tubular conti'ol member, and the abrasive moves with uniformity and free from undesirable aircurrent disturbances and is directed from the discharge outlet of the tubular control member immediately and directly onto the inner end of the blades as they pass the discharge outlet.

The centrifugal abrasive propelling machine herein disclosed is made of so constructed as to insure proper and speedy assembly thereof for most efliclent operation. The

. tubular control member 0, the impeller 11, and the hub member h can each be made as a one-piece casting. The side wall plates I and 2 and the spacing studs 3 can be made of steel and the blades b can be made of a suitable wear-resisting metal, sufllciently tough to resist the shocks and metal fatigue incident to operation.

While certain novel features of the invention havebeen disclosed and are pointed out in the annexedclaims, it will be understood that various omissions, substitutions and changes may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. In an abrading machine, a rotor having a plurality of blades terminating short of the axis of rotation of admitting space, a tubular abrasive, feeding device extending into said abrasive admitting space, said feeding device havingan abrasive discharge outlet in the to direct abrasive into the path of rotation of said blades, means for supplying abrasive to said feeding device positioned forwardly of said discharge outlet, an impeller rotatably mounted feeding device operative to through the discharge outlet 2. In an abrading machine, a rotor having spaced radially extending abrasive propelling blades mounted for rotation at high speed, a tubular control member normally held in stationary position within said rotor, said control member having'an abrasive discharge outlet in the sidewall thereof, a conduit for supplying abrasive to said control member positioned forwardly of the discharge outlet therein, a rotatably mounted impeller positioned within said tubular control member having impeller vanes operative to eject abrasive through said discharge .outlet into the path of rotation of said blades, and means including a guide passage and an abrasive driving element associated with said tubular control member and said impeller pomtioned rearwardly of said discharge outlet for moving stray abrasive into a position where it will be thrown by said impeller vanes through said discharge outlet.

3. In an abrading apparatus, a rotor adapted to be driven at high rotative speed having a pluextending blades thereon, said blades extending inwardly short of the axis of rotation of said rotor to define a central abrasive admitting space, a tubular control member having relatively few parts.

said rotor to define an abrasive tubular sidewall thereof operative element associated with said i or circular movement associated withsaid feeding an abrasive 7 helical H v:

' the rear side discharge outlet in the tubular side-wall thereof axially spaced from the rear edge of said tubular control membenan impeller positioned within' said tubular control member and fixed to rotate with said rotor, said impeller having a plurality of abrasive propelling vanes axially positioned between the side edges of said blades operative to throw abrasive through said discharge outlet into the path of rotation of said blades, 'means for supplying .abrasive to said impeller, and a e associated with the inner surface of said'tubular control member for returning stray abrasive into a position where the same will be swept out of the discharge outlet of said tubular control member by said impeller vanes.

4. In an abrading machine, 'a rotor having a plurality of blades terminatingshort of the axis of said rotor to define an abrasive admitting space, a tubular abrasive feeding device extending into said abrasive admitting space, said feeding device having anabrasive discharge outlet .in the tubular side wall thereof operative to direct the abrasive into the path of rotation of said blades, means for supplying abrasive to said feeding device, and a helical passage extending along the inner surface of said tubular feeding device from the rear edge thereof to the vicinity of said discharge outlet, said passage being operative to guide stray abrasive located rearwardly of the adjacent rear side edge of said outlet to a position where it maybe discharged through said discharge outlet.

5. In an abrading machine, a rotor having a plurality of blades terminating short of the axis of said rotor,to define an abrasive admitting space, a tubular abrasive feeding device extending into said abrasive admitting space, said feeding device having an abrasive discharge outlet in the tubular sidewall thereof operative todirect the abrasive into the path of rotation of said blades, means for supplying abrasive to said feeding device, and a helical rib fixed to the inner surface of said tubular feeding device and extending from the vicinity of the rear -edge of said feeding device to the vicinity of said discharge outlet, said rib defining a helical passage operative to guide stray abrasive forwardly to a position where it may be discharged through said discharge outlet. v

6. In an abrading machine, a rotor having a plurality of blades terminating short of the axis of rotation of said rotor to define an abrasive admitting space, a normally stationary tubular abrasive feeding device extending into said abrasive admfiiting space, said feeding device having an abrasive discharge outlet in the tubular side wall thereof, an impeller having a plurality of abrasive propelling vanes mounted for rotation and operative to throw abrasive through said discharge outlet and into the path of rotation of said blades, said impeller having a fan element associated therewith positioned rearwardly of said propelling vanes operative to create a current of air which resists movement of stray abrasive in said tubular feeding device rearwardly of edge of the discharge outlet therein.

'1. In an abrading machine, a rotor having a plurality of blades terminating short of the axis of rotation of said rotor to define an abrasive admitting space, a normally stationary tubular abrasive feeding device extending into said abrasive admitting space, said feeding device having an abrasive discharge o'utlet'in the tubular side wall thereof, an impeller having -a plurality of abrasive vanes mounted for rotation sive admitting space,

and operative to throw abrasive through said discharge outlet and into the path of rotation of said blades, said impeller having a plurality 'of fan elements positioned rearwardly of said impeller vanes, said'fan elements being operative upon rotation thereof to create a current of air which resists movement of stray abrasive in said tubular feeding device rearwardly-of the rear side edge of the discharge outlet therein.

8. In an abradingmachine, a rotor having 5 plurality of blades terminating short of the axis of rotation of said rotor to define an abrasive admitting space, a normally stationary tubular abrasive feeding device extending into said abra-, sive admitting space,'said feeding device having an abrasive discharge outlet in the tubular sidewall thereof, an impeller having a plurality of abrasive propelling vanes mounted for rotation and operative to throw abrasive through said discharge outlet and into the path of rotation of said blades, means associated with the inner surface of said tubular feeding device for guiding stray. abrasive located rearwardly of the adjacent rear side edge of said discharge outlet in a direction forwardly towards said discharge outlet, and means associated with said impeller operative to drive said stray abrasive forwardly towards the discharge outlet in said feeding device.

v9. In an abrading machine, a rotor having a plurality of blades terminating short of the axis' of rotationof admitting space, a normally stationary. tubular abrasive feeding device extending into said abraan abrasive discharge outlet ill the, tubular side 1 wall thereof, aconduit for supplying abrasive to said feeding device positioned forwardly of said discharge outlet, an impeller havinga plurality of abrasive propelling vanes mounted for rotation and operative to throw abrasive through said dis-' charge outlet and into" the path of rotation of said blades, and cooperating abrasive guiding and abrasive driving means asoclated with said tubular feeding device and said impeller positioned rearwardly of said discharge outlet and said vanes operative to move stray abrasive forwardly towards the discharge outlet in said feeding device.

10. In an abrading machine, a rotor having a plurality of blades terminating short ofthe axis of rotation of said rotor abrasive feeding device extending into said abrasive admitting space, said feeding device having an abrasive discharge outlet in' the tubular side wall thereof axially spaced between the side edges of said blades, an impeller having a plurality of said rotor to define an'abrasive said feeding device having.

to define an abrasive, admitting space, a normally stationary tubular abrasive propelling vanesv fixed to rotate with said rotor 'and operative to throw abrasive through said discharge outlet and into the-path of rotation of said blades, and cooperating means associated with said tubular feeding device and said impelleroperative toi'drive stray abrasive forwardly towards the discharge outlet insaid feeding device, said cooperative means including a helical passage extending along the inner surface of said feeding device from the vicinity of the rear edge thereof to the vicinity of said discharge outlet, and a fan element associated with said impeller positioned rearwardly of said propeller vanes in cooperative relationship to said helical passage. 1

11. In an abrading machine, a hub member having a'central opening, a drive shaft having one end thereofextending intos'aidopeninm-a,

rotor disk mounted on said hub and having a central opening, abrasive propelling blades supported by said rotor disc and terminating short of the axis of rotation of said disc to define a admitting space, a tubular control member extending into said central space having the rear edge thereof extending into a circular recess provided in said hub member, said tubular control member having an abrasive discharge outlet in the'side wall thereof of limited peripheral length and positioned between the side edges of said blades, an impeller fixed to said hub member operative to forceably eject the abrasive through the discharge opening in said tubular control member and means for supplying abrasive to said impeller, said hub member having passages therein leading from said circular recess to the exterior of said hub.

12. In an abrading machine, a rotatably mounted drive shaft, a hub member mounted on said shaft, a rotor including a disk mounted on said hub member and having a central opening,

abrasive propelling blades mounted on said disk and extending inwardly to a point substantially in axial alignment-with the peripheral edge of the central opening in said disk, the inner ends of said blades defining a central abrasive-receiving space, a tubular control member extending into said central abrasive-receiving space, an

ejecting abrasive supplied thereto through the discharge outlet of said control member and into the path of rotation of said blades, said impeller including a disk-shaped rear wall portion, a plurality of abrasive propelling vanes mounted on said portion, a collar portion having a diameter substantially equal in diameter to said diskshaped said collar portion seating against the inside face of said hub mem ber,,a key element engaging said hub member, drive shaft and said collar portion for retaining the same,

in fixed position, and means for securing said impeller to the end of said drive shaft.

13. In an abrading machine, a rotor havinga plurality of blades terminating short of the axis of rotation of said rotor to define an abrasiveadmitting space, a tubular abrasive feeding device extending into said abrasive-admitting space, said feeding device having an abrasive discharge'outlt in the tubular side wall thereof, a feed spout for supplying abrasive to said feed ing device, and means for supporting said feed spout and said feeding device in operative position, said supporting means including a main bracket positioned entirely to one side of said feed spout and tubular feeding device, a saddle member adjustably connected to and extending laterally from said main bracket for supporting said feeding device, and means adjustably connected to and extending laterally from said main bracket and above said tubular feeding device for supporting said feed spout.

14. In an abrading machine, a rotor having a plurality of blades terminating short of the axis of rotation of said I admitting space, a tubular abrasive feeding device extending into said abrasive-admitting space, said feeding device having an abrasive discharge outlet in the tubular side wall thereof, and means for supporting said feeding device in operative including a main rotor to define an abrasivelaterally from and adjustably connected to said main bracket, said saddle member having an arcuate surface upon which a tubular face of said abrasive feeding device is positioned, and a clamping bar adjustably secured to said saddle member extending partially into said abrasive feeding device for removably securing said feeding device to said saddle member.

15. '"In an abrading machine, a rotor having a plurality of blades terminating short of the axis of rotation of said rotor to define a central space, a tubular'abrasive feeding device extending into said central space, said feeding device having an abrasive discharge outlet in the tubular side wall thereof operative to direct the abrasive into the path of rotation of said blades, an abrasive feed spout for supplying abrasive to said rotor, a feed funnel positioned over the abrasive receiving end of said feed spout, and means for supporting said feed spout and feed funnel in operative position, said supporting means including a main bracket fixedly positioned entirely to one side of said feed spout, a secondary bracket connected to said feed funnel and adjustably secured to and extending laterally from said main bracket, winged portions extending laterally from the upper end of said feed spout, means for removably connecting said winged portions to said secondary bracket and a'saddle member connected to and extending laterally from said main bracket for supporting said feeding device.

16. In a centrifugal abrading machine, a rotatably mounted shaft, a rotor head fixed to said shaft, abrasive throwing blades supported by said rotor head extending inwardly short of the axis of rotation of said head to define a central space, a tubular control member extending into said central space having an abrasive discharge outlet in the tubular side wall thereof, abrasive supply means for conducting abrasive into said tubular control member, a rotatably mounted impeller positioned within said tubular control member operative to eject abrasive through said discharge outlet and into the path of rotation of said blades, an abrasive discharge passage extending through said rotor head point adjacent the inner end of said tubular control member, and means associated with said tubular control member defining an abrasive passage extending from adjacentthe inner end of said tubular control 'member to the discharge outlet therein for guiding stray abrasive.

1'7. In a centrifugal abrading machine, a rotatably mounted shaft, a rotor head comprising a hub member fixed to said shaft and a side wall disc fixed to said hub member, abrasive throwing blades supported by said disc member extending inwardly short of the axis of rotation of said head to define a central space, a tubular control member extending into said central space having an abrasive discharge opening in the side wall thereof, abrasive supply means for conducting abrasive into said tubular control member, impeller means positioned within said tubular control member for ejecting abrasive through the discharge opening in said tubular control member into the path of rotation of said blades, said hub member having a cavity therein into,which the innerend of said tubular control member ex;- tends, said hub member having a. vent passage extending from said cavity outwardly to the exterior thereof.

18. In a centrifugal abrading machine, a rotatably mounted shaft, a rotor head mounted on said shaft, abrasive throwing blades sup axially and rearwardly from a p rte y s id rotor head extendin inwardly tionary tubular abrasive feeding device extendin short of the axis of rotation of said head to deinto said space, said feeding device having an fine a central space, a tubular control member abrasive discharge outlet in the tubular side wall extending into said central space having an thereof, abrasive supply means for conducting abrasive discharge opening in the sidewall thereabrasive into said tubular abrasive-feeding device of, abrasive supply means for conducting abrasive positioned forwardly of the discharge outlet into said tubular control member, impeller means therein and an impeller mounted on saidshaft positioned within said tubular control member and having a plurality of abrasive propelling for ejecting abrasive through the discharge openvanes extending into said feeding device and log in said tubular control member into the path operative to throw abrasive. through said disof rotation of said blades, said rotor head having charge outlet and into the path of rotation of a groove extending continuously around the said blades, said rotor head having a rotatable inner end of saidtubular control member, pockets portion rearwardly of said abrasive discharge in said rotor head opening into said groove, and outlet in said abrasivefeeding device, said rotata vent passage extending from each of said able portion having air inlet ports extending pockets to the exterior of the rotor head. therethrough to admit air into said tubular 19. In a centrifugal abrading machine, a abrasive feeding device, whereby to balance any rotatably mounted shaft, a rotor head comprising differences in pressure in said abrasive admitting a hub member fixed to said shaft and a side space resulting from the high speed rotative wall disc fixed to said hub member, abrasive movement of said bladed rotor head.

throwing blades supported by said disc extending 21. In a centrifugal abrading machine, a

inwardly short of the axis of rotation of said rotatably mounted shaft, a rotor head mounted head to define a central space, a tubular control to rotate with said shaft, abrasive throwing member extending into said central space having blades supported byv said rotor head extending an abrasive discharge opening in the side wall inwardly short of the axis of rotation of said head thereof. an abrasive supply means for conducting to define a central space, a tubular control memabrasive into said tubular control member, imber extending into said central space and having peller means positioned within said tubular conan abrasive discharge opening in the side wall trol member for ejecting abrasive through the thereof, abrasive supply means for conducting discharge opening in said tubular control memabrasive into said tubular control member, imber into the path of rotation of said blades said peller means positioned within said tubular conhub member having a groove extending control member for ejecting abrasive through the tinuously around the inner end of said tubular discharge opening in said tubular control memcontrol member, pockets in said hub member exher into the path of rotation of said blades, said tending outwardly from said groove, and a vent rotor having a rotatable portion rearwardly of passage extending from each of said pockets in a the abrasive discharge opening in said control generally axial direction outwardly to the exmember, said rotatable portion having a cavity terior of said hub member. therein into which the inner end of said tubular 20. In an abrading machine, a drive shaft control member extends, the rotatable portion of mounted for high speed rotation, a rotor head said rotor head having'a plurality of vent pasfixed to said drive shaft, a plurality of blades sages therein leading from the exterior of the mounted on said head and terminating short of rotor head to the cavity to admit air to the inthe axis of rotation of .said rotor head to define terior of the tubular control member.

an abrasive admitting space, a normally sta- CHESTER E.UNGER. 

